The invention is based on a fuel pumping device for an internal combustion engine operating in accordance with the two-cycle principle.
Such a fuel pumping device is known from DE 37 27 266 A1. This document describes a diaphragm piston pump, which delivers and compresses fuel for operating an injection device. To this end, the fuel is supplied to the diaphragm piston pump from a fuel tank via a pre-delivery pump. The fuel which is compressed there is delivered to the injection valve. The diaphragm piston pump is provided with motive force by the pulse air diverted out of the crankcase of the internal combustion engine. To this end a diaphragm is seated on the piston compressing the fuel, on which the pulse air acts on the side facing away from the piston. The overpressure being created in the crankcase during a combustion cycle actuates the compression piston. A mechanical spring, together with the underpressure in the crankcase during the compression cycle of the two-cycle engine, performs the return stroke of the compression piston.
A comparable diaphragm piston pump for a fuel injection device is described in DE 41 25 593 A1, wherein the return stroke of the compression-piston takes place by means of a leaf spring package. The spring rate of the leaf spring package can be mechanically changed by means of an adjustment screw.